During their 2012 Winter Study, Michigan Technological University population biologist John Vucetich and wildlife ecologist Rolf Peterson started wondering where the wolves of Isle Royale National Park had gone. They only found nine wolves, and as far as they could tell, only one was a female. They expressed serious concern that the wolves of Isle Royale might be well on their way to extinction.

Now they know what happened to at least three of those wolves, one of them a young female, who likely would have contributed to the population’s viability in the future.

In late May, National Park Service biologist Ted Gostomsk reported one or more animal carcasses floating in water in a deep, 19th century mine shaft at Isle Royale. With the aid of the Park Service, Peterson and his wife, Carolyn, went in to investigate. They recovered and examined what was left of the animals and then collected the bones..

“We found there had been a real catastrophe in early winter, before we arrived on the island in January,” said Vucetich. “There were three dead wolves from the Chippewa Harbor Pack in the shaft: a collared male that we had been unable to locate this winter, an older male—maybe the alpha male—and a female born in 2011…